Units for the Expression of Both Static and Dynamic Work in Similar Terms, and Their Application to Weight-Lifting Experiments

Abstract

The author contends that work as defined by the physicists (measured in ergs) is badly adapted for use by physiologists studying muscular performance and has led to serious errors in estimates of muscular efficiency. For example, to support a load against gravity certainly requires muscular effort, but no work is done on it if work is defined in the classic physical manner. A new mathematical approach was explored which was designed to overcome the difficulty. By measuring the vertical component of motion in a new frame of reference, as if from a freely falling object, the physiological conception of the tension time can be extended to meaure the"work" performed on a load; when it is started, moved, stopped, or supported without motion; in similar units (dyne-seconds). The general expression is [image]ax being the vertical component of acceleration, and ay the horizontal component, both measured from a fixed point on the earth''s surface; m the mass, and Wp the "work" being sought. This conception solves the old physiological problem of expressing the "static" and "dynamic" work done on a load in similar terms.